# define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>


int main()
{
	int arr[10] = { 0,1,2,3,4,5,6,7,8,9 };
	int x = 0;
	for (int i = 0; i < 10; i++)
	{
		x ^= arr[i];
	}

	for (int i = 0; i < 11; i++)
	{
		x ^= i;
	}
	printf("%d", x);
}